1. Field of the Invention
The present invention relates to a device for operating a side airbag, and more particularly to a device for operating a side airbag with a simple structure which does not include an electronic control unit (hereinafter referred to as "ECU") for determining whether the airbag has to be deployed or not.
2. Description of the Prior Art
To protect occupants of a vehicle in the event of a collision, various safety devices have been developed. An airbag system, one of the safety devices, prevents the occupants from directly colliding with a solid body of the vehicle by means of an inflated airbag. The airbag system generally comprises a crash sensing portion such as an accelerometer, an ECU for determining whether the airbag has to be deployed or not and connected to the crash sensing portion to receive a signal therefrom, a gas generating portion for generating gas in response to an airbag deploying signal outputted from the ECU, and an airbag module for deploying with gas generated from the gas generating portion. The gas generating portion is formed of a squib for receiving the airbag deploying signal to explode and an inflator for generating gas to inflate the airbag module. The squib is exploded by the airbag deploying signal received, and thus the inflator is also exploded to generate gas.
Currently, in order to protect occupants in the event of a side collision as well as a front collision, it is a general tendency that a side airbag is installed additionally. Meanwhile, the time required to fully deploy a side airbag after collision should be shorter than the time required to fully deploy the front airbag, because a distance between front-seat occupants and a front vehicle body is longer than the distance between the front-seat occupants and a side vehicle body. Therefore, 5"-30 ms standard (See David S. Breed & Vittbrio Castelli, "Problems in Design & Engineering of Air Bag Systems", SAE Technical Paper Series #880724 p. 1-30, 1988.) for a front airbag system can not be used in a side airbag system.
To protect occupants from collision in the side airbag system, the determination whether the airbag is to be deployed should be completed within 15 ms from collision, Because of this reason, an ECU of 16 bits or above is utilized in the side airbag system, while an ECU of 8 bits is generally used in the front airbag system. With the ECU of 16 bits or above, the side airbag system becomes expensive. Also, in spite of using the ECU of 16 bits or above, there is the possibility that the determination time becomes long, because data to be processed in the ECU could be suddenly increased, whereby the reliability of the airbag system is deteriorated.